Split & Splat is one of 4 songs added in the August Update. Like all battle songs, it has a random chance of being played during online matches. It can also be heard in Squid Beatz.
In Splatoon 2, Split & Splat can be unlocked to listen in Squid Beatz 2 as a final reward from the Inkling Girl (Splatoon 2)amiibo. It cannot, however, be heard anywhere else in the base game. It has a maximum score of 146 and 321 in Normal and Hard modes, respectively.
Other versions
Split & Splat (Stay Fresh Trailer)
The song was first heard in the Stay Fresh Trailer for the August Update. Near the beginning of the song, it moved one of the sections forward, leading to a longer instrumental opening, with vocals only coming in at around 25 seconds.